Mixing : Automation : Automation Modes : Write Mode

Write Mode
Write mode writes automation from the time playback starts to the time it stops, erasing any previously written automation for the duration of the automation pass.
AutoMatch can be applied to a Write automation pass. See AutoMatch Time.
“After Write Pass, Switch To” Option
You can set Pro Tools to automatically change to Touch mode or Latch mode, or remain in Write mode after the completion of an automation pass in Write mode.
To set the Automation mode after a Write pass:
1 Choose Setup > Preferences and click Mixing.
2 Under Automation, select an After Write Pass, Switch To option (Touch, Latch, or No Change).
3 Click OK to close the Preferences window.